Science Highlights

Trace metals in deep ocean waters: A review

A synthesis on the data available on the distribution of selected trace metals (i.e. Cadmium, Cobalt, Copper, Molybdenum, Nickel, Lead and Zinc) in the deep ocean from 1979 to 2009 is provided by Aparicio-González and colleagues (Aparicio-González et al., 2012). This article also identifies patterns as well as gaps in currently available data in terms of their capacity to depict their global distributions.

A great contribution for the GEOTRACES Programme !

Aparicio_2012Figure: Geographic location of reported depth profiles (1000 m or deeper) for all studied elements together, as of 1976 to 2009. Colors scale indicates the number of deep profiles per 100,000 km2. Source: Journal of Marine Systems


Aparicio-González A., Duarte CM., Tovar-Sánchez A. (2012), Trace metals in deep ocean waters: A review, Journal of Marine Systems 100–101 (26-33), DOI : 10.1016/j.jmarsys.2012.03.008

A global compilation of the neodymium isotopic composition of seawater for GEOTRACES

GEOTRACES will allow the collection of numerous data that will be archived in the GEOTRACES Data Assembly Centre (GDAC), and will eventually contribute to create a world atlas of tracers in the ocean. However, data acquired on GEOTRACES core parameters in the framework of past cruises could also be considered in this gathering. With this aim, François Lacan and co-authors (Lacan at al, 2012) propose a commented compilation of the neodymium (Nd) isotope and concentration data published before September 1st, 2011. A very interesting tool for modellers and any other scientist following works on this tracer!


Figure: εNd averaged between the surface and 400 m depth. Figure made with Ocean Data View (Schlitzer, 2009).
Source: Author manuscript, definitive and authenticated version published in "Chemical Geology 300-301 (2012) 177-184"

Read more: A global compilation of the neodymium isotopic composition of seawater for GEOTRACES

New strategy to evaluate trace element fluxes to the ocean from aerosols

HsiehScientists participating in GEOTRACES have developed a new strategy to evaluate trace element fluxes to the ocean from aerosols (Hsieh et al, 2011). The new approach uses the common geochemical behaviour of two isotopes of the same chemical element (thorium;Th), whose sources to the surface seawater are totally different (and independent). 230Th is a decay product of the homogeneously distributed 234U in seawater and provides a measure of the residence time of Th element in surface waters. This residence time is applied to 232Th content of the same water column. Because 232Th derives from dust from weathered rocks and enters the ocean surface waters in aerosols, knowing its amount and residence time allows reconstruction of the input of aerosol to the ocean surface. Hsieh and co-workers successfully applied this approach in the central Atlantic Ocean, including an assessment of aerosol fluxes associated with the dust plume blowing from South American over the South Atlantic (see photo).

This new method is now being incorporated into GEOTRACES cruises across the Atlantic and beyond.


Yu-Te Hsieh, Gideon M. Henderson, Alexander L. Thomas (2011), Combining seawater 232Th and 230Th concentrations to determine dust fluxes to the surface ocean Earth and Planetary Science Letters, 312 (3-4) DOI: 10.1016/j.epsl.2011.10.022

Measuring precisely with only 40 ml of sample

BrulandIt is now possible to measure precisely manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) concentrations in seawater using only 40 ml of sample.

All the cooking recipes and techniques are given in the recent detailed article of Dondra Biller and Kenneth Bruland in Marine Chemistry (Biller and Bruland, 2012). A work full of perspectives for trace metal measurements in the framework of GEOTRACES. Don't miss it!

Read more: Measuring precisely with only 40 ml of sample

Recent and original results in the Southern Ocean on mercury speciation and cadmium isotopes

AU_cruise_lowFor the first time detailed mercury (Hg) speciation was determined along an Australia-Antarctic section (Cossa, et al., 2011) and cadmium (Cd) isotopes along a South Africa-Antarctic section (Abouchami W., et al., 2011). Both were acquired along two IPY-GEOTRACES sections: SR3 CASO-GEOTRACES (GIPY6) and ZERO&DRAKE (GIPY5) respectively.

Hg species distribution suggests distinct features in the Southern ocean Hg cycle: (i) a net atmospheric Hg deposition on surface water near the ice edge, (ii) Hg enrichment in brines during sea-ice formation and (iii) a methylmercury maximum close to Antarctica, far from anthropogenic Hg emissions (Figure 1).

Cd isotope ratios and concentrations are distributed into two distinct Cd isoscapes, delimiting two biogeochemical provinces the Antarctic Circumpolar Current (ACC) and Weddell Gyre (Figure 2). A doubling of the isotope effect due to biological consumption of Cd is observed during water transport from the Weddell Sea into the ACC. The increase in the magnitude of Cd isotope fractionation, as a result of enhanced phytoplankton biomass and altered species composition in the Southern Ocean, demonstrates that Cd isotopes could potentially serve as a useful measure of biological productivity.

Read more: Recent and original results in the Southern Ocean on mercury speciation and cadmium isotopes

 Data Product (IDP2017)


 Data Assembly Centre (GDAC)


Subscribe Mailing list

Contact us

To get a username and password, please contact the GEOTRACES IPO.

This site uses cookies to offer you a better browsing experience. Find out more on how we use cookies and how you can change your settings.